Willie Nelson turns 80 next week, but the festivities got underway last Thursday night in Nashville, where a star-studded cast of duet partners featuring Neil Young, Sheryl Crow, Norah Jones, Jamey Johnson, Ashley Monroe and Leon Russell paid tribute to the outlaw country icon at an intimate birthday soiree. The celebration – held at Jack White's Third Man Records – doubled as a taping for an upcoming CMT Crossroads episode.

Crossroads has raised eyebrows in the past with odd-couple pairings like Def Leppard and Taylor Swift, or Aerosmith and Carrie Underwood, but when it came to Willie Nelson, Thursday night's cross-generational cast of characters didn't make such strange bedfellows. White perhaps best explained why when he introduced Nelson – "Nothing says America like the man that's gonna play."

And with that, Shotgun Willie – all smiles, boasting braids and clad in black – took the stage, opening up with his 2012 ode to Acapulco Gold, "Roll Me Up and Smoke Me When I Die." Whether that – the only sans-guest selection of the 13-song set – was the singer making poignant reference to his own mortality or a timely reference two days before 4/20, the song set the tone for a joyous hour of warts-and-all renditions and ragged collaborations.

Of all the guests, Young was the only one who played his own songs (not that anybody complained), as well as the only guest who joined Nelson to perform as an unaccompanied duo. Although Young's appearance wasn't a surprise to the 100 or so attendees who packed the makeshift TV studio in Third Man's warehouse/office space (and, unfortunately, not the adjoining record store/compound's cozier live music venue, the Blue Room), it was as though the audience couldn't really believe they'd witness the Godfather of Grunge rock out with the Redheaded Stranger in such close confines until they actually saw it. And Young diehards probably couldn't believe what they were hearing when the singer busted out the rarely-performed, resplendent Rust Never Sleeps lullaby "Sail Away," which he performed standing almost nose to nose with Nelson at center stage.

"I wrote it for my car, but it works for you great," Young joked in barroom-chum fashion before serenading Nelson with his next number, a spellbinding rendition of the 1976 Stills-Young Band classic "Long May You Run." Strumming and swaying back and forth, eyes obscured by a baseball cap, his voice sounding pristine as if preserved in time, Young mostly sang it directly to Nelson, not to the crowd or the cameras. With White, Johnson and Monroe watching enchanted from the wings, it was a moment not lost on anyone but maybe the man of the hour, who was keeping a close eye on his friend and fellow Farm Aid organizer's left hand for the chord changes, making the rawness all the more real.

Uncharacteristic of most musical TV tapings, this one went off with only one do-over: Nelson and Crow had trouble finding the key on a countrified duet of the pop-vocal standard "Faraway Places" (which also featured Jones on piano) the first time around. But Crow put forth her finest Patsy Cline without a hitch when she tackled Nelson's most famous composition, "Crazy."

"I'm just doing this as an homage to the man I love, or else I wouldn't touch it," Crow said of the song.

But a little sonic dissonance is par for the course when it comes to Nelson, whose inability to turn in a polished performance is a signature strength that's endeared him all the more with age (not to mention that it imposed a healthy dose of spontaneity to this taping). Nelson kept duet partners on their toes with his unmistakably weathered talk-singing, slip-sliding in and out of time over their verses, like when singing Fred Rose's "Blue Eyes Crying in the Rain" with Monroe. And he threw his nine-piece pickup band of session vets curveballs with each trademark wobbly, walking guitar solo, played on the most iconically beat-to-shit acoustic ax in country music. His solo on "Angel Flying Too Close to the Ground" was one for the ages when it comes to lyrical pickin', not to be outdone by a glass-shattering vocal delivery from Monroe.

The juxtaposition of roughness and refinement reached its peak with Norah Jones' jazzy interpretation of "Funny How Time Slips Away." On that one, Willie's single-string staccato riffage cut through Jones' smoky, sensual croon like interference from an old A.M. radio, wafting straight out of an early Texas morning and right into a midnight Manhattan speakeasy.

Jamey Johnson, perhaps the most musically devoted Willie Nelson footstep-follower of the bunch (and easily the most morbidly depressive country singer since Townes Van Zandt), let the low notes ring out as he bellowed a sparse, tragically hopeless version of the love requiem "Permanently Lonely." Luckily, Willie and Jamey picked up the pace, and the tone, with a foot-stomping, shambolic "Shotgun Willie."

Each of the guests – save for Leon Russell, who had a Music City gig of his own to get to and had pre-taped his performance in rehearsal – returned to the stage for a rollicking all-star finale of "Whiskey River," followed by Crow leading the crowd in singing "Happy Birthday."

The CMT Crossroads episode is expected to air in late June. Proceeds from Nelson's annual birthday bash in Austin, on April 28th, will benefit the volunteer fire department of West, Texas, where last week a fertilizer plant explosion left 14 dead and scores more injured.